1. Field of the Invention
The present invention relates to a color meter which measures the respective intensity of the blue, green and red regions of an illuminating light source to provide photographic information according to the measured values.
2. Description of the Prior Art
A color meter is required to determine a color correcting filter, which can be used to compensate for the difference between the color balance of the illuminating light source and that of the film to be used. Color correcting filters, a LB filter and a CC filter which are respectively different in achieving correction can be used. The color correction is performed through the combination of the filters. Namely, the LB filter is used for compensating for the difference between the inclination of the entire color balance ranging from the red to the blue in the light source and the inclination of the corresponding entire color balance of the film to be used. Also, the CC filter is used to locally compensate the difference between the color balance of a specified color region with respect to the red in the light source and the corresponding color balance of the film to be used.
The conventional color meter measured and displayed the incident light intensity ratio (B-R ratio) of the blue region with respect to the red region in the light source and the incident light intensity ratio (G-R ratio) of the green region with respect to the red region. A photographer uses a calculation panel on the color meter or an accessory calculation panel and operates the dial on the calculation panel in accordance with the color temperature of the film and the B-R and G-R ratios read by the color meter. He reads the corresponding light balancing factor or the color compensating factor to determine the LB filter or the CC filter.
Therefore, the conventional color meter having such a construction as mentioned above was considered as an accessory for measuring and displaying the B-R ratio and G-R ratio, which were only indirect information in determining the LB filter or the CC filter, resulting in that the conventional color meter took more time to determine the correcting filter and was too complicated in use. Briefly described, according to the conventional color meter, the information measured was intermediate in determining the correcting filter. The B-R ratio and the G-R ratio reflects the measured information of the light intensity in each of the blue, green and red regions. The final output was a value, which had no direct information. The filter determination which is based on the film used must be calculated or determined by use of an accessory calculator panel.